Radioreception



Sept. 11, 1928.

P. G. WEILLEQR RADIO nscnrnon Filed April 25, 1924 lil Patented Sept.11, 1928 UNITED 'STATES. rATEN-rorncn ram. G. WEILLEE, 02 EAST ORANGE,NEW JERSEY, Assienoa 'ro WIRED Elmo, mo, on NEW Yonx, n. Y., aconronarron E DELAWARE.

RADIORECEPTION.

This invention relates to the rcceptionof I wireless telephone andtelegraph signals by means of vacuum tubes and associated tuningcircuits. 5 It is the object of the present invention to provide animproved circuit arrangementfor .the reception of wireless signalswhereby selectivity and ease of control are greatly increased anddistortion of the receivedsignal is materially reduced. a a

In this improved form of receiver vacuum 7 tubes of the three-electrodetype are .em-

ployed. An inductance is connected in the usual manner in thegrid-filament circuit, and this inductanceis closely coupled to anotherinductance of approximately the same value which is connected at one endto the plate of the vacuum tube. When this inductance is connecteddirectly to the plate, the telephones and source ofenergy for the platecircuit are connected between the filament and late in the usual manner,The tuning of tie grid and plate circuits is preferably accomplished Iby means of a single variable condenser which is connected either acrossthe grid inductance or across the late inductance. It is possible forthis sing e condenser to tune both circuits simultaneousl The incomingenergy is supplied to thegrid circuit through an inductance which isloosely coupled to the combined rip-plate inductances. This looselycoupled j be in the antenna circuit or other circuit from 5 which theenergy to be received is supplied. If the relative values of thecomponent parts of these receivers are correct, the vacuum tube willnormally oscillate, and thev ,variation of thesingle condenser willserve to to vary the'fre uency of the oscillations. The

variation of tie coupling between the antenna inductance and the grid,inductance will ser e to control the oscillations in the vacuum ubecircuits, but will not materially 5 vary the tuning of these circuits ifthe inductive and capacity coupling between the an- 7 v tennainductanceand the grid inductance is sufficiently small. .Better controlof the oscil-' lations is obtained b coupling to either the .0 grid onthe plate in uctance, or both, an inductance shunted by a variable highresistance. MWhen the resistance is adjusted to the correct value,oscillation of the tube will" cease, but the received signal intensitwill 5 be undiminished. Apparently' 'any a rpby virtue of the close"coupling of the grid and plate inductances;

inductance may tion of energy by this controlcircuit is offset by theincreased voltage on the grid due to c iange in phase betweenthereceivedvoltage and current caused by the resistance.

In order to receive a signal ofan unknown. wave length with thisreceiver, ,the single variable condenser is .varied until thecharacteristic beat notes of autodyne reception are heard, and thecondenser is then set so that the receiver is tuned between the beatnotes of the received si al. The-antennacircuit is then tuned'until themaximum of energy is received. The antenna coupling maythen be varieduntil the oscillation of the receiver ceases. Or the oscillation of thereceiver'can be eliminated by adjusting the resistance across theinductance associated with the grid or plate circuit until the correctvalue is found.

The ordinary regenerative receiver when tuned by the zero beatmethod,-th at is when both plate and grid circuits are tuned alike, 1sextremely critical, and gives great-distortionof the received signal.With the present circuit,'however, there is no difliculty in tuning, asthere is but one tuning control (aside fromany antenna'tuning thatjmaybe provided) andthe other control. serves merely toeliminate theoscillation which causes the distortion in an ordinary regenera- 'tivereceiver.

This invention is readily adapted to radio frequency amplification, andmakes such amplification possiblewithout distortion or disturbingoscillation. The change from the circuit just described is small; Achoke coil is substitutedfor the telephones, and either end of theplateinductance is connected through a'condenser to the gr id of anothervacuum tube'which may be used as a de- 9 tee-tor. In this circuitarrangement it' is par ticularly advisable to utilize an inductanceassociated with the, grid or plate inductance of the radio frequencytube and shunted by a variable high resistance'to control the osoilla- Ytions of the radio frequency tube and thus .preventdistortion. 1

It has been found that particularly good operation can be obtained withthe specially wound coils hereinclaimed andwherein the grid and platecoils are simultaneously wound on the same form. This will be morepartioularly described. hereinafter, but it is to be understoodv thatthe invention isnot limited to this particular. embodiment.

A clearer understanding of the invention may be had from the followingdescription of the preferred embodiment illustrated in the accompanyingdrawings.

In these drawings,

Fig. 1 illustrates in detail a preferred form of winding for the closelycoupled grid and plate coils;

Fig. 2 illustrates the completely grid and plate coils; and

Fig. 3 shows the antenna inductance coupled to the combined grid andplate inductances and means for varying the coupling between thesecircuits.

It has been found that the operating characteristics of the circuit areespecially good when the inductances are wound as illustrated in Fig. 1.Diagonal slots suchlas 16 of Fig. 1 (16, 17, 18, 19 of Fig. 2) are cutin a dielectric frame 20. The two coils are then wound on this frameworkin the manner illustrated in Fig. 1. The winding of the grid coil 4, forexample, is begun at 2'1, and the winding of the plate coil 5 is begunon the opposite side of the frame but close to the grid coil. WVhen theslot 16 is reached, the coil 4 is led through the slot and continuesalong the obverse side of the frame, whereas the coil 5 is led throughthe slot and continues along the reverse side of the frame. When theslot 17 is reached, the, opposite procedure takes place and the coilsare thus wound side by side but on opposite sides of the frame work. Thewinding thus continues until the desired amount of inductance is woundon the frame. It has been found that this method of winding gives. avery compact inductance element in which the inductive coupling isapproximately 80% and the capacity coupling is sufiicient to give thedesired characteristics to the plate and grid circuits and make itpossible to tune them to the same frequency simultaneously by onecondenser.

It is to be understood, of course, that these coils may be wound on aframe having more than four slotsin it. v

In Fig. 3, 22 represents the side of a container for this radioreceiving set Within which the combined antenna and grid inducwoundtances 23 and the antenna inductance 24 are cord 25 which is wound on .areel 26 preferably controlled from the outside of the cabinot by meansof a knob 27. The spring 28 tends to maintain the inductance 24 in itsnormal vertical position'.- This arrangement of apparatus has been foundto give particularly good results, but it is not intended to limit thepresent invention in any way to the embodiment illustrated.

I claim:

1. A combined inductance for the grid and plate circuits of a vacuumtube receiver comprising a frame having a plurality of radial slotstherein, a wire wound on said frame beginning at the center andalternating from one side of the frame to the other at each slot,asecond winding begun simultaneously with said first winding and fromthe same point but on the opposite side of said frame and continuingwith said first mentioned winding but always on the opposite side ofsaid frame.

2. A combined inductance comprising a flat support having an even numberof substantially radially disposed slots and two windings engaged insaid slots with the turns of one overlying the turns of the other anddisposed at opposite sides of the support.

3. A combined inductance comprising two windings wound in zigzag fashionto opposite sides of a common plane with the turns of one windingsupported on the turns of the other winding at the points of crossingfrom one side to the opposite side of the common plane and with thesections of the two windings between such crossings disposed to oppositesides of the common plane.

4. A combined inductance comprising a grid winding and a plate windingarranged in non-variable closely coupled relation with each turn of onewinding immediately overlying a turn of the other winding and crossed toopposite sides of an intermediate plane to position the adjacentsections of the two windings substantially parallel at opposite sides ofthe intermediate plane.

5. A combined inductance made up of a plurality of windings crossed inthe course of each turn to opposite sides of an intermediate plane withthe turns of one winding supported on the turns of the other winding atsuch points of crossing and adjacent sections of the different windingsat opposite sides of the intermediate plane. p In witness whereof, Ihave hereunto set my hand this 12th day of April, 1924.

PAUL G. WEILLEl't.

